In conventional practice, intramedullary nails are driven down through the medulla of a fractured bone, usually one of the long bones of the leg. The nail is provided with holes through which locking bolts or retaining pins are inserted transverse to the nail and bone to secure the nail in the desired position. The locking bolts retain the nail against rotation and longitudinal movement.
In most cases after the nail is inserted into the bone, a first locking bolt is inserted through the bone and through a transverse borehole in the nail towards the distal end of the nail. One or more additional bolts are then inserted through holes near the proximal end of the nail. This procedure is difficult because the transverse locking bolts must meet their respective boreholes precisely, even though these holes are covered by bone and soft tissue. The hole at the distal end of the nail is particularly difficult to locate as it is remote from the area of the surgeon's incision. To locate the boreholes, sighting mechanisms which use X-ray imaging are employed. This technique is complicated and can lead to a high radiation dosage for the patient and possibly for the surgeon. Meanwhile, if the hole location is incorrectly identified, part of the bone is destroyed unnecessarily.